Which contains covalent bonds? tibr4 ca(no3)2 bcl4- bacl2

Explanation:

A covalent bond is formed when an element shares its valence electron with another element. This bond is formed between two non metals.

An ionic bond is formed when an element completely transfers its valence electron to another element. The element which donates the electron is known as electropositive element and the element which accepts the electrons is known as electronegative element. This bond is formed between a metal and an non-metal.

, and ,contain ionic bonds as they are made up of metals and non metals.

As is made up of boron and chlorine which are both non metals, it contains covalent bonds.

that's what i got you can count the number of atoms